Five kittens, and a Full-grown dog badly affected by hartz flea drops

Well, my cat had her first litter aever, and she, having fleas from hell(Can’t blame her, she was found in a crazy-cat-lady’s house.).
We waited until the package said it was safe to apply, 12 months(I think.).
We put the drops on early in the day, and the cats HATED it.
Mid-day they were acting odd, and by night, they started having petiete-mals(Zoneing out, and shaking.) . My mom was freaking out and told me to come here(Here being her doorway.)
“Look at her.”

“What?”

“At her paws!”

“There… shaking?”

She and I took the cats into the bathroom and washed them thuroughly, three cats that weren’t too lucky, suffered long-term brain damage:
One meows inccesently(not a trait from before) and had odd occurances of staring at, or swiping candle fires. The other seems to suffer from a cat form of nervosa-anorexia, as she refuses to eat. The last one has sporadic twitches.
There mother seems to act the same asbefore, though, more mean.

More recently, we used this on our dog, and he had advrze, but diffrent affects.
His eyes drooped, he was lethargic. over all, looked liek he was going to die.
My father washed him, and the VERY next day, he acted like he did when he was a little puppy.

We Will never used Hartz again, And I hope that the company no longer makes flea/tick drops for animals.

DO NOT use Hartz, they WILL hurt your animal. It doesn’t matter the age or their weight, as this dog was seven years old(May be old for a dog, but he was still a randy dog.), Breed(The dog was a german shepard, the cats were solids, calicos, and allycats.), And this dog also weighed at the least 80 pounds.(Not quite sure.)